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Wednesday, October 31, 2007

Tonight, I found a message by my mum on my mailbox - she was quite excited and told me that I should absolutely have a look at this new comet, I probably would have heard about it, and that it was such a great view, so well visible now, have a look at the constellation of Perseus...

Comet Holmes, not in my skylight,but photographed at 0800 UT on October 30, 2007 at Costa Mesa, California - via Wikipedia.Now, the net has been fullofreportsaboutcomet Holmes these last days. However, I hadn't really taken note of it - but tonight, the sky above Frankfurt was clear, just a bit misty, bright stars and constellations are clearly visible, and Perseus was close to the zenith - so I looked out of the skylight, and there was comet Holmes: A grey blob to the naked eye, and a quite impressive grey blob in Sabine's grandfather's old binoculars! There is no tail yet, but the blob has some structure, and the comet is bigger than Halley at it's return in 1985/86.

You can find the comet roughly halfway between the bright star Capella in the northern sky and the W of Cassiopeia - have a look at the sky map from heavens above, for example. It's impressive!

It's a Jupiter-Family-Comet, meaning that, while of course it orbits the Sun, its orbital dynamics are driven by Jupiter's strong gravity; C. Holmes' period is something like 6.5 years. The weird thing about this comet is that this brightening occurred way past perihelion (which occurred I think in May of this year), while the comet is moving away from the Sun and it's now somewhere between the orbits of Mars and Jupiter.

In any case, the first night of brightening was I think Oct. 25th, at which day it looked to me just like a star of ~3rd magnitude to the naked eye distorting the usual shape of the constellation Perseus. With binoculars you could see that there was some fuzzyness to it, and with a good telescope it was definitely non-stellar: nice star-like nucleus, surrounded by a spherical coma, no trace of a tail then. Observed it for a few more days, but the past couple of days have been cloudy here in NorCal...Maybe tonight.

thanks for sharing the photo! How did you take it? Did you somehow fix the digicam to a small telescope? That's not just the zoom of the camera? And what was the exposure time? You know, one of the reasons why I am sometimes thinking about a new digital camera is that it seems that they are pretty good now for taking astronomy pictures...

I didn't know that the comet is already moving away from the Sun, hm, what a pity, that means that it probably will not become any brighter and larger with a prominent tail and all this? Wikipedia states that the tail is pointing away from us, so that's the reason it appears as a more or less spherical blob - but OK, if it's already beyond the Mars orbit, that sounds reasonable.

That's a cool shot, to see a comet when the tail is pointing straight away...so nice and round.BTW has anyone gotten a handle on why and how some comets emits so much X-ray, considering their relatively low temperatures?

The closeup photo (using 5" f8 refractor..1016mm focal length) shows some interesting near nucleus activity. You can see a "negative" bow-shock.

I forgot the counterweights for my German equatorial mount!! In true amateur-astronomy fashion, I jury rigged a quick fix..2 8 amp-gel cells duct taped to the shaft. I also brought my 8" f1.5 Schmidt-Camera (using hypered TP2415 film), with the hope of photographing the faint ion tail. I forgot my ice-box..containing the film & film holder!!??

I should have further opportunities to photograph the comet thru Sunday. This offroad race is out in the desert (California & Nevada state-line).

Stefan, Yes, it's just the camera's zoom. 12x at that!(36mm-432mm) I used a Canon Powershot S3 IS. I haven't yet tried the 4x of digital zoom, but I'm sure the final photo will not look good.The exposure is limited to only 15s, so that's how long I could keep the shutter open.(at F4.0)

And yes, digital cameras are simply everywhere in amateur astrophotography, and especially the DSLRs (modded and unmodded). In fact, I first wanted to get a digital camera a few years ago mainly to take pictures of the sky, but I now do more like "normal" photography. :D

Here are some images from 11/5 from Hungry Valley/CA (east of Santa Barbara, where B used to work). I'm just beginning to get the "hang of things" after 3 yrs of inactivity in amateur astrophotography. The revolution in digital SLR is impacting this field, & these are some of my 1st DSLR astrophotos.

I went out 2 days later (Wed, 11/7) & got some more photos. Tail looks different. I also got in a closeup shot of the nucleus w/jet. I also found a new observation area, there are some nice panoramic views of the comet w/Milky Way. I observed 3 neg magnitude meteors..very memorable. 1 had a red nucleus, that left a persistent-trail.

It was really beautiful in the mountains, I did some 4x4'ing afterwards. Bad weather until about Monday.

thank you for sharing your photos of the comet - they look great! Unfortunately, the sky above Frankfurt has been cloudy since last week, so I have had no chance to spot comet Holmes again since last wednesday...

[ I'm here for the 40th anniversary of the Baja 1000 Many international racers are here like rally star Armin Schwarz from Germany. ]

I've been photographing Comet Holmes for 2 nights (11/12 & 11/13), & the wildly dynamic ion tail seems to have disappeared.My 8" f1.5 Schmidt-Camera might have picked up something, but I have to develop the film once I get back home.